Beefy Boxes and Bandwidth Generously Provided by pair Networks
Problems? Is your data what you think it is?

Re^3: Search and replace

by Bharath666 (Novice)
on Jan 31, 2013 at 15:59 UTC ( #1016345=note: print w/ replies, xml ) Need Help??

in reply to Re^2: Search and replace
in thread Search and replace

Also if you don't mind can you please explain me how exactly this command works

$found =~ s/ENV{\"(.*?)\"}/\$ENV(\"$1\")/g;


Comment on Re^3: Search and replace
Download Code
Replies are listed 'Best First'.
Re^4: Search and replace
by Athanasius (Canon) on Jan 31, 2013 at 16:23 UTC

    I thought I already had. :-) But OK, let’s add an /x modifier to the regex to make it easier to break apart:

    $found =~ s/ ENV{\" # match the characters: ENV{" (.*?) # followed by any characters -- this sequence +is the "value", and the parentheses capture it into the special varia +ble $1 \"} # followed by: "} / \$ENV( # and substitute a literal: $ENV(" $1 # followed by the captured "value" \") # followed by: ") /gx; # and repeat the search & replacement to the e +nd of $found


    • The double quotes are backslashed only because I was using a one-liner (and I’m on Windows). This is unnecessary in a .pl script. (But the $ must be backslashed to show that it is literal, not the special symbol for “match the end of a line” (in the search part) or a sigil denoting a scalar variable to be interpolated (in the replacement part). Update: Added the words from “(in the search part)” to the end of the sentence.)

    • The ? in the capture group (.*?) makes the match non-greedy. So the regex engine looks for the fewest number of characters occurring between ENV{" and "}. Without the ?, the match would be greedy, and on the string:


      it would match

    • which is not what we want!

    Hope that helps,

    Athanasius <°(((><contra mundum Iustus alius egestas vitae, eros Piratica,

      Yeah!! I got it now :) Thanks a lot :)

Log In?

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://1016345]
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others browsing the Monastery: (3)
As of 2015-11-29 13:18 GMT
Find Nodes?
    Voting Booth?

    What would be the most significant thing to happen if a rope (or wire) tied the Earth and the Moon together?

    Results (750 votes), past polls